try...catch needed in async call inside useEffect?-CodePudding

I'm trying to do some async stuff in a useEffect hook. So first I define the async function and second I'm calling that function. I am not quite sure how to handle errors correctly. Is the try...catch part also needed as the .catch of the function call? Isn't it the same?

useEffect(() => {
  const fetchData = async () => {
    try {
      const token = await AsyncStorage.getItem('auth.token')
      // do something
    } catch (e) {
      console.error(e)
    }
  }

  fetchData().catch(console.error)
}, [])

CodePudding user response：

You have two options to handle asynchronous operations in JavaScript, you can use async await or .then() & .catch(). Here is an example of both:

useEffect(() => {
  const fetchData = async () => {
    try {
      const token = await AsyncStorage.getItem('auth.token')
      // do something
    } catch (e) {
      console.error(e)
    }
  }

  fetchData()
}, [])

useEffect(() => {
  const fetchData = () => {
    AsyncStorage.getItem('auth.token')
      .then(token => console.log(token))
      .catch(err => console.error(err))
  }
  fetchData()
}, [])